The Dahua IP recorder changes the network configuration itself

Hello,
I have a problem with the Dahua IP recorder, for several days I have been struggling with the constantly changing network configuration on the device.
I set the recorder to the internal network 192.168.xx, then I set this address in the DMZ in Router and at this point everything works fine, I have access to monitoring from inside and outside. The problem appears after a few working hours, when I can no longer connect to the recorder, neither in the internal nor external network. The recorder itself is on, but the network configuration is totally changed. Ip address changed to some 10.179.114.x, DNS 1.2.3.4
And now when I try to set it up again, when I try to save the settings I get a message that ipv6 has not been configured. So I switch to ipv6 and see that all the fields are empty, I click default and go back to ipv4 and now after clicking save everything works again ... for a few hours and everything is back again. Have any of you encountered a similar problem?

Set a static address instead of DHCP.

Sorry, I forgot this important thing. DHCP on the device is turned off

What is this recorder?
Has 2 network cards?

Sorry for so long, but the registrar is currently at the other end of Poland and I have to contact an employee in that area.
Well, the employee misled me, it is not a Dahua recorder, but a BCS NETWORK VIDEO RECORDER NVR0801E

Puzieekk wrote:

later in Router I set this address in DMZ

You are giving the green light to the bluntest script kiddie to hack this NVR
What do you need to do ?:
1. Disable the DMZ
2. Disable Upnp
3. Redirect ports on the router other than standard: that is, not 37777 and 37778 and port 80 also to another.
4. Delete users 888888 and 666666 and make new ones. Admin, of course, the password is also set to its own.
5. Don't let telnet outside.
It doesn't guarantee 100% certainty anyway, but at least it makes breaking in a lot more difficult.

User 666666 was deleted and all the rest had passwords changed, I'll change passwords and I'll try.

If you don't disable DMZ and you don't redirect ports to non-standard ones, changing passwords alone won't do anything.

Unfortunately, it did not help, I got information from the distributor that the recorder is infected with viruses and the cost of restoring it to operation is about PLN 50-100 net and waiting for about 6 weeks. Currently, a new properly configured recorder is going to the site

On the website of the importer of this equipment, there is a method on how to "virus" the equipment.
It usually works. "Corrective action"
And the most important - what has already been written above:
http://www.bcscctv.pl/webpage/bcs-line-bezpieczenstwo.html

Hello raffin. Unfortunately, the method of "virus removal" did not work in my case. The importer replied to my e-mail that they are waiting for the problem to be solved (three weeks already). What to do next? I don't know.